@GG1 4877 posted:
Way back in the day, Hyrdocal was my go to product. I'm talking 35 years ago plus. Is is still made and who is the current manufacturer? The foam should have some fairly good support though if you don't plan on putting any heavy loads on it, such as foot or something.
Woodland Scenics carries Hydrocal Light - supposed to be just as strong and lighter.
Walmart also has it online.